<template>
    <div class="play">
      <!-- 模糊背景(靠样式设置), 固定定位 -->
      <div
        class="song-bg"
        :style="`background-image: url(${
          songInfo && songInfo.al && songInfo.al.picUrl
        }?imageView&thumbnail=360y360&quality=75&tostatic=0);`"
      ></div>
      <!-- 播放页头部导航 -->
      <div class="header">
        <van-icon
          name="arrow-left"
          size="20"
          class="left-incon"
          @click="$router.back()"
        />
      </div>
      <!-- 留声机 - 容器 -->
      <div class="song-wrapper">
        <!-- 留声机本身(靠css动画做旋转) -->
        <div
          class="song-turn ani"
          :style="`animation-play-state:${playState ? 'running' : 'paused'}`"
        >
          <div class="song-img">
            <!-- &&写法是为了防止报错, 有字段再继续往下访问属性 -->
            <img
              style="width: 100%"
              :src="`${
                songInfo && songInfo.al && songInfo.al.picUrl
              }?imageView&thumbnail=360y360&quality=75&tostatic=0`"
              alt=""
            />
          </div>
        </div>
        <!-- 播放按钮 -->
        <div class="start-box" @click="audioStart">
          <span class="song-start" v-show="!playState"></span>
        </div>
        <!-- 播放歌词容器 -->
        <div class="song-msg">
          <!-- 歌曲名 -->
          <h2 class="m-song-h2">
            <span class="m-song-sname"
              >{{ songInfo.name }}-{{
                songInfo && songInfo.ar && songInfo.ar[0].name
              }}</span
            >
          </h2>
          <!-- 歌词部分-随着时间切换展示一句歌词 -->
          <div class="lrcContent">
            <p class="lrc">{{ curLyric }}</p>
          </div>
        </div>
        <!-- 留声机 - 唱臂 -->
        <div class="needle" :style="`transform: rotate(${needleDeg});`"></div>
      </div>
      <!-- 播放音乐真正的标签
        看接口文档: 音乐地址需要带id去获取(但是有的歌曲可能404)
        https://binaryify.github.io/NeteaseCloudMusicApi/#/?id=%e8%8e%b7%e5%8f%96%e9%9f%b3%e4%b9%90-url
       -->
       <audio
        ref="audio"
        preload="true"
        :src="`https://music.163.com/song/media/outer/url?id=${id}.mp3`"
      ></audio>
    </div>
  </template>
  
  <script>
  // 获取歌曲详情和 歌曲的歌词接口
  import { getSongByIdAPI, getLyricByIdAPI } from '@/api'   
  import { Icon } from 'vant'
  export default {
    components: {
      [Icon.name]: Icon,
    },
    name: 'play',
    data() {
      return {
        playState: false, // 音乐播放状态(true暂停, false播放)
        id: this.$route.query.id, // 上一页传过来的音乐id
        songInfo: {}, // 歌曲信息
        lyric: {}, // 歌词枚举对象(需要在js拿到歌词写代码处理后, 按照格式保存到这个对象)
        curLyric: '', // 当前显示哪句歌词
        lastLy: '' // 记录当前播放歌词
      }
    },
    computed: {
      needleDeg() { // 留声机-唱臂的位置属性
        return this.playState ? '-7deg' : '-38deg'
      }
    },
    methods: {
      async getSong() { // 获取歌曲详情, 和歌词方法
        const res = await getSongByIdAPI(this.id)
        this.songInfo = res.data.songs[0]
        // 获取-并调用_formatLyr方法, 处理歌词
        const lyrContent = await getLyricByIdAPI(this.id)
        const lyricStr = lyrContent.data.lrc.lyric
        this.lyric = this._formatLyr(lyricStr)
        // 初始化完毕先显示零秒歌词
        this.curLyric = this.lyric[0]
      },
      _formatLyr(lyricStr) {
        // 可以看network观察歌词数据是一个大字符串, 进行拆分.
        let reg = /\[.+?\]/g // 
        let timeArr = lyricStr.match(reg) // 匹配所有[]字符串以及里面的一切内容, 返回数组
        console.log(timeArr); // ["[00:00.000]", "[00:01.000]", ......]
        let contentArr = lyricStr.split(/\[.+?\]/).slice(1) // 按照[]拆分歌词字符串, 返回一个数组(下标为0位置元素不要,后面的留下所以截取)
        console.log(contentArr);
        let lyricObj = {} // 保存歌词的对象, key是秒, value是显示的歌词
        timeArr.forEach((item, index) => {
          // 拆分[00:00.000]这个格式字符串, 把分钟数字取出, 转换成秒
          let ms = item.split(':')[0].split('')[2] * 60
          // 拆分[00:00.000]这个格式字符串, 把十位的秒拿出来, 如果是0, 去拿下一位数字, 否则直接用2位的值
          let ss = item.split(':')[1].split('.')[0].split('')[0] === '0' ? item.split(':')[1].split('.')[0].split('')[1] : item.split(':')[1].split('.')[0]
          // 秒数作为key, 对应歌词作为value
          lyricObj[ms + Number(ss)] = contentArr[index]
        })
        // 返回得到的歌词对象(可以打印看看)
        console.log(lyricObj);
        return lyricObj
      },
      audioStart() { // 播放按钮 - 点击事件
        if (!this.playState) { // 如果状态为false
          this.$refs.audio.play() // 调用audio标签的内置方法play可以继续播放声音
        } else {
          this.$refs.audio.pause() // 暂停audio的播放
        }
        this.playState = !this.playState // 点击设置对立状态
      },
      showLyric() {
        // 监听播放audio进度, 切换歌词显示
        this.$refs.audio.addEventListener('timeupdate', () => {
          let curTime = Math.floor(this.$refs.audio.currentTime)
          // 避免空白出现
          if (this.lyric[curTime]) {
            this.curLyric = this.lyric[curTime]
            this.lastLy = this.curLyric
          } else {
            this.curLyric = this.lastLy
          }
        })
      }
    },
    mounted() {
      this.getSong()
      this.showLyric()
      console.log(this.$route.query.id);
    }
  }
  </script>
  
  <style scoped>
  .header {
    height: 50px;
  }
  .play {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 1000;
  }
  .song-bg {
    background-color: #161824;
    background-position: 50%;
    background-repeat: no-repeat;
    background-size: auto 100%;
    transform: scale(1.5);
    transform-origin: center;
    position: fixed;
    left: 0;
    right: 0;
    top: 0;
    height: 100%;
    overflow: hidden;
    z-index: 1;
    opacity: 1;
    filter: blur(25px); /*模糊背景 */
  }
  .song-bg::before{ /*纯白色的图片做背景, 歌词白色看不到了, 在背景前加入一个黑色半透明蒙层解决 */
    content: " ";
    background: rgba(0, 0, 0, 0.5);
    position: absolute;
    left: 0;
    top: 0;
    right: 0;
    bottom:0;
  }
  .song-wrapper {
    position: fixed;
    width: 247px;
    height: 247px;
    left: 50%;
    top: 50px;
    transform: translateX(-50%);
    z-index: 10001;
  }
  .song-turn {
    width: 100%;
    height: 100%;
    background: url("./img/bg.png") no-repeat;
    background-size: 100%;
  }
  .start-box {
    position: absolute;
    width: 156px;
    height: 156px;
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    display: flex;
    justify-content: center;
    align-items: center;
  }
  .song-start {
    width: 56px;
    height: 56px;
    background: url("./img/start.png");
    background-size: 100%;
  }
  .needle {
    position: absolute;
    transform-origin: left top;
    background: url("./img/needle-ab.png") no-repeat;
    background-size: contain;
    width: 73px;
    height: 118px;
    top: -40px;
    left: 112px;
    transition: all 0.6s;
  }
  .song-img {
    width: 154px;
    height: 154px;
    position: absolute;
    left: 50%;
    top: 50%;
    overflow: hidden;
    border-radius: 50%;
    transform: translate(-50%, -50%);
  }
  .m-song-h2 {
    margin-top: 20px;
    text-align: center;
    font-size: 18px;
    color: #fefefe;
    overflow: hidden;
    white-space: nowrap;
    text-overflow: ellipsis;
  }
  .lrcContent {
    margin-top: 50px;
  }
  .lrc {
    font-size: 14px;
    color: #fff;
    text-align: center;
  }
  .left-incon {
    position: absolute;
    top: 10px;
    left: 10px;
    font-size: 24px;
    z-index: 10001;
    color: #fff;
  }
  .ani {
    animation: turn 5s linear infinite;
  }
  @keyframes turn {
    0% {
      -webkit-transform: rotate(0deg);
    }
    100% {
      -webkit-transform: rotate(360deg);
    }
  }
  </style>